1. Field of the Invention
The apparatus of the present invention relates to wireline operations in the recovery of oil and gas. More particularly, the present invention relates to a protective liner in a wireline sub assembly system for eliminating excessive wear on the interior wall of the assembly portion or a saver sub portion of the assembly.
2. General Background of the Invention
In conducting wireline operations, many types of tools are positioned on the lower end of a wireline, which is a steel cable or the like, lowered into the well bore in order to undertake certain tests downhole. Because in the past there has been difficulties in undertaking wireline work with the potential hazard of blowouts in the well, there has been developed and patented by the present inventor, a side entry sub assembly which is patented under U.S. Pat. No. 4,681,162 and reissued under U.S. Pat. No. RE 33,150. This patented device, which is placed below the top drive on the rig floor, includes a side entry portion which enables the wireline to extend through the side entry passage and into the main passage and downward into the drill string. One of the problems that has been confronted with using the entry assembly by itself is that as the wireline extends down through the angulated passage in the tool, at the point that it exits the bottom of the wireline assembly into the borehole, it tends to make contact with the inner wall of the assembly. As the wireline is moved up and down through the borehole, it would literally wear or cut into the wall. Therefore, as part of the patented combination, the wireline assembly includes a lower sub having a male end portion, which is threadable into the lower end of the wireline assembly, so that the wireline makes contact with the upper end of the sub, and if any damage to the interior is done, it is done to the interior wall of the sub, a product which is inexpensive and can be replaced quite easily.
However, over the years, the side entry sub assembly has experienced problems with excessive wireline wear in the lower end of the side entry tool and the saver sub. Therefore, the applicant has devised a system whereby the side entry tool itself and the saver sub can be fabricated or modified in order to avoid excessive wireline wear on the assembly and the sub which would result in savings by eliminating damage to the tool body and by eliminating the need for the replacement of subs on a regular basis.